• Research Highlights
Psychotic disorders are serious illnesses that disrupt the way a person thinks, feels and perceives the world. People with these disorders, which include schizophrenia and other disorders with psychotic symptoms, have better outcomes if they receive early and comprehensive care. Without such care, people with psychosis often find it difficult to participate in work, school, or relationships, and may experience significant impairment or disability.
Studies from other countries have found demographic differences in the rates at which psychotic disorders are diagnosed. However, few studies have examined these rates in US populations. New research funded by the National Institute of Mental Health (NIMH) found disparities in diagnoses of psychotic disorders and showed that such diagnoses are associated with a range of negative health outcomes.
What did this study look at?
Researchers led by Winston Chung, MD at Kaiser Permanente and Kathleen Merikangas, Ph.D., and Diana Paksarian, Ph.D., at the NIMH Intramural Research Program examined trends in the diagnosis of psychotic disorders in the United States from 2009 to 2019.
The study was a retrospective chart review, meaning the data was collected from the patients’ existing medical records. Researchers reviewed records for nearly 6 million patients treated at a large health care system in Northern California. Among the information they gathered was:
- Demographic characteristics, including self-reported race and ethnicity
- Medical diagnoses, including psychotic disorders and other mental disorders and physical conditions
- Negative health outcomes and behaviors, including lack of health care utilization
Participants were categorized in two ways. The first was in one of seven racial and ethnic groups: African American or Black. American Indian or Alaska Native. Asian American? Latino or Hispanic? Native Hawaiian or Pacific Islander. non-Hispanic White; or “other” racial and ethnic group, which included people who identified as multiple races or ethnicities. The second involved those who had only one psychotic disorder (non-emotional psychotic disorder) or a psychotic disorder accompanied by symptoms of a mood disorder such as bipolar disorder or depression (emotional psychotic disorder).
The researchers determined the number of psychotic disorders diagnosed in each study year and compared how those rates changed over time and among different racial and ethnic groups. Additionally, they examined whether experiencing a psychotic disorder was associated with a higher likelihood of being diagnosed with another medical condition or experiencing negative health outcomes.
What did the study results show?
Diagnoses of psychotic disorders were stable (for some groups) over time.
Overall, rates of psychotic disorders remained relatively stable over the 10-year study period. Throughout the years, non-emotional psychotic disorders were diagnosed more than affective psychotic disorders.
Black participants consistently had the highest rates of diagnosis for both types of psychosis, while Asian participants had the lowest rates. Non-emotional psychotic disorders significantly decreased in White and Asian participants over time, whereas they increased significantly for participants whose racial and ethnic group was “other”. Rates of affective psychotic disorders were stable for all groups over time.
Diagnoses of psychotic disorders differed between racial and ethnic groups.
The next series of analyzes examined the likelihood of being diagnosed with a psychotic disorder based on racial and ethnic group membership. White participants were used as the reference group because they constituted the largest group in the study.
Data suggest differences in diagnoses of psychotic disorders based on race and ethnicity. Patterns differed for non-emotional compared to affective psychotic disorders.
- For non-emotional psychotic disorders, Black and American Indian or Alaska Native participants were more likely to be diagnosed. Hispanics, Asians, and other participants were less likely to be diagnosed.
- For affective psychotic disorders, the probability of diagnosis was again higher for Black and American Indian or Alaska Native participants as well as for Hispanic participants. The probability of diagnosis was lower for Asians, Hawaiian or Pacific Islanders, and other participants.
Psychotic disorders were associated with other health conditions and negative outcomes.
The final set of analyzes examined associations between psychotic disorders and other health conditions and negative health outcomes. People with a psychotic disorder were more likely to be diagnosed with another mental disorder, most commonly, bipolar disorder, substance use disorder, or depression. Similarly, people with a psychotic disorder were more likely to have a comorbid condition, such as obesity, diabetes, and cardiovascular disease such as stroke, and to have died by suicide. People with a psychotic disorder were also less likely to have visited a health care provider in the past year – despite already being enrolled in a health care system.
Together, these results highlight the pervasive and serious health risks of having a psychotic disorder, resulting in poorer mental and physical health and an increased risk of premature death. Combined with evidence of racial and ethnic disparities in rates of psychotic disorders, the findings underscore the disproportionate health impacts faced by specific groups in the United States.
What do the results tell us?
This study is notable for collecting comprehensive clinical data from a large registry of diverse Americans over an extended period. However, the sample came from one health care system in one US state, so the results may not generalize to rates of mental illness in other parts of the country. It will be useful to repeat the results in additional samples.
However, the results confirm a high health burden associated with psychotic disorders, including a range of co-occurring mental and physical conditions and preventable causes of death. Patients with a psychotic disorder were also significantly less likely than patients without a disorder to seek health care.
Importantly, rates of psychotic disorders—and their associated health risks—were not equally distributed across racial and ethnic groups. And, although rates of psychotic disorders were mostly stable over time and even declined for some groups, this trend was not seen across all groups.
In addition, several of the disparities identified related to affective psychotic disorders. This finding highlights the importance of training health care providers to recognize mood disorders and manage the full range of psychotic and emotional symptoms their patients may experience.
What can researchers and clinicians do next?
According to the researchers, these findings point to several avenues for future research. First, having identified disproportionately higher or increasing rates of psychotic disorders among specific racial and ethnic groups, researchers could examine the factors that cause these disparities and whether they can be reduced by tailoring care or prevention efforts to specific populations. Additionally, this study used broad racial and ethnic categories (for example, Asian), which may obscure differences for individual subgroups (for example, Chinese, Filipino). Investigating whether diagnostic patterns are the same across racial and ethnic categories would add important information to our understanding of disparities as they relate to psychotic disorder diagnoses.
It is also important to determine whether the data reflect real differences in the rates at which people experience psychotic disorders in the United States. There are potential unmeasured factors that may have influenced the results. For clinicians, these include misdiagnosis and unconscious biases, such as a greater willingness to diagnose certain groups with a stigmatized condition. In addition, there are known differences in access to treatment, health care knowledge, and quality of care between racial and ethnic groups that may have affected the likelihood of seeking and receiving effective mental health care.
To fully understand and address disparities in psychotic disorders in this country, more comprehensive, prospective studies assessing a wide range of influences and outcomes are needed. Among the factors that future studies could examine are socioeconomic status, adverse childhood events, experiences of interpersonal and structural racism, and social determinants of health.
Report
Chung, W., Jiang, S.-F., Milham, MP, Merikangas, KR, & Paksarian, D. (2023). Disparities in the incidence of psychotic disorders among racial and ethnic groups. American Journal of Psychiatry, 180(11), 805–814. https://doi.org/10.1176/appi.ajp.20220917
